Q. I’m currently remodeling a vacation home where the copper plumbing has developed pinhole leaks because of an acid water condition. To save money, my client wants to replace the copper pipes with CPVC plastic, but my plumber says that’s a bad idea. Who’s right?

A.Al King responds: I agree with your plumber. Plastic pipe resists acidic water better than copper does, but it’s a "band-aid" solution — the root of your problem is the water, not the pipes. Even if all your pipes are plastic, the acidic water will cause problems with other parts in the system — riser tubes in the toilet, brass faucets, parts of the water heater, and so on. Also, acidic water affects the flavor of food and drinks made with it. So I advise installing an acid neutralizer (the most widely known is the Culligan system). That will cost about $1,200.

Acidic water aside, plastic pipe is still an option worth considering. But I would recommend cross-linked polyethylene tubing, not CPVC. The main reason to use plastic tubing in a remodeling job is to save labor, because it’s flexible enough to snake around obstacles. It usually requires less demolition, less drilling, and fewer joints. But CPVC tubing is rigid, and will actually have a higher labor factor than copper.

If you do install flexible plastic tubing, go with a "home-run" system: Use a dedicated line for each fixture, running back to a central manifold panel (see "Home-Run Holds Promise," JLC 8/90).

A home-run system can use either cross-linked polyethylene or the less expensive polybutylene. On my own house, I’d trust the polybutylene, but for a customer, I’d recommend the polyethylene because it doesn’t have the reputation problem polybutylene has. The failures that have happened with polybutylene were caused not by the tubing but by problems with the acetyl fittings used at the joints, and the newer brass fittings don’t have the same troubles. All the same, a homeowner who might want to sell his house sometime is best advised to avoid polybutylene.

For that matter, if quality is your object, I’d stick with copper. It’s the only product with a proven 50-year track record of success. If you solve the acidic-water problem at its root — which you should anyway — copper plumbing will give you a lifetime of satisfaction, and then some.

Al King operates a heating and plumbing contracting business in Perkasie, Pa.